As a means for mutually exchanging information by a plurality of users, a mailing list using an electronic mail, an electronic bulletin board using WWW (World Wide Web) and a chat, are widely used. In the mailing list, a plurality of electronic mails are collected and collectively sent as a message to all members. In the electronic bulletin board, a space to jointly own information is set on a network, and a plurality of registered users or anonymous users can freely enter a message. In the chat or online chat room, in the same way of the electronic bulletin board, the space to jointly own information is set and a text message can be exchanged in real time.
In a communication means aiming at message exchange of many users such as the mailing list, the electronic bulletin board and the chat, a message related to a topic in which a majority of participants is interested is often exchanged. In this case, a group of users who exchange an electronic message with common purpose or interest is called “a community”.
In an information exchange system on the network, if the number of messages to exchange becomes large, a user often misses important information included in the message or it is difficult for the user to understand the contents appeared or discussed over a plurality of messages. Accordingly, a system for extracting predetermined information included in the plurality of messages and for preserving as information resource different from the plurality of messages is proposed.
For example, as a method for extracting schedule data from information of personally received electronic mail based on a rule to extract daily event and for presenting the schedule data, Japanese Patent Disclosure (Kokai) PH9-269940 “Device for Extracting Date or the like”, and “Extraction of Schedules and T0-P0 Items from E-mail Messages by Identifying Messages Structures and Using Language Expressions” (A thesis of Information Processing Society, Vol. 40, No. 10, pp. 3694-3705, 1999), are known. Furthermore, as a method for extracting date information from an information source except for the mail and for displaying the date information in a calendar format, Japanese Patent Disclosure (Kokai) P2000-215213 “Method and System for Preparing Table based on Distributed Type Documents” is known. Furthermore, in the community system, as a method for preserving document information corresponding to a plurality of messages in order to manage information apt to be embedded in the message, Japanese Patent Disclosure (Kokai) P2002-140344 “Method and Device for Document Management” is known.
In such a communication system in which a plurality of users exchange and jointly own the message, it is difficult for the user to remember which message includes important information in case of necessary the important information, and the user must repeatedly read a large number of messages in case of information to be often referred. However, in case of jointly owning a simple retrieval result, reutility is scarce because the presentation format is simple and unnecessary information often mixes.
Furthermore, important information exists in the message, in addition to date information such as a meeting program or a schedule, arranged by collecting other's comment or reply for a topic or a question, and arranged by collecting a predetermined expression or format part (such as URL (Uniform Resource Locator) accessible by WWW and mail address) included in the message.
On the other hand, if each user personally arranges the important part included in information such as the mail exchanged by communication among a plurality of users, operation efficiency is bad. In addition to this, an important event (information or status) cannot be jointly owned among the users communicating each other because important information is different for each user. Furthermore, even if collected information is jointly owned by disclosure, it is necessary for the user to check permission of inspection for the collected information or permission of reference for information (such as the mail from which the important item is extracted).
The above-mentioned problem does not occur when each user simply arranges information from personal mails. However, the above-mentioned problem occurs in the community system in which a plurality of users exchanges and jointly owns the message. Accordingly, a system for easily generating an important information extraction rule and an extraction result, and for jointly owning the extraction rule and the extraction result, is necessary.